Scalar axion field of toroidal electromagnetic pulses

TL;DR

This paper shows that toroidal electromagnetic pulses in free space can naturally produce localized pseudoscalar fields due to axion electrodynamics, highlighting structured light's potential to exhibit axion-like properties.

Contribution

It demonstrates that superpositions of toroidal pulses inherently generate localized pseudoscalar fields, extending Maxwell's theory with axion electrodynamics.

Findings

Localized pseudoscalar fields co-propagate with structured light pulses.

Toroidal electromagnetic pulses exhibit regions with non-zero E·B.

The result clarifies a consequence of axion electrodynamics, not axion particle generation.

Abstract

Axion electrodynamics extends Maxwell's theory by postulating a hypothetical pseudoscalar axion field sourced by a scalar product of electric and magnetic fields. In this work, we demonstrate that a superposition of toroidal electromagnetic pulses propagating in free space naturally exhibits localized regions, where $\bm{E}\cdot\bm{B}\ne0$. As a consequence of axion electrodynamics, these structured light pulses generate a space-time localized pseudoscalar field co-propagating with the pulses. This result should not be interpreted as a mechanism for generating axion particles by light, but rather as a consequence of adopting the axion electrodynamics extension to Maxwell's equations.